- Email: [email protected]
Histamine alteration in h-APP transgenic mice with Alzheimer's disease
Abstracts / Cell Biology International 32 (2008) S1eS67 5 Department of Neurology and Center for Alzheimer Disease, Southern Illinois University School of Medicine, Springfield, IL,USA, 62794
Reduced brain or neuronal activity and metabolism may play an important role in Alzheimer’s disease (AD) etiology, as suggested by epidemiological and imaging studies in humans. Stimulatory experimental paradigms, e.g., environmental enrichment, voluntary exercise and learning, reduce the levels and accumulation of amyloid peptides (Ab) in the cerebral cortex of transgenic mouse models of AD. Neuronal hypoactivity in the rat olfactory bulb, induced by naris-occlusion, elevates protein levels and activity of b-secretase-1 (BACE1), a prerequisite for Ab genesis. We determined BACE1 expression relative to endogenous neuronal activity, measured by cytochrome c oxidase (CO) reactivity, in the adult rhesus monkey (Macaca mulatta) striate cortex (V1) and guinea pig barrel cortex (SI) following whisker trimming. BACE1 expression in V1 occurred mainly in the neuropil over layer II-IV, appearing as alternating patches of high and low immunoreactivities. The periodic patches of BACE-1 immunoreactivity correlated spatially with CO blob and inter-blob areas, but the labeling intensities of the two markers were complementary to each other within a given area. In SI, BACE-1 expression in the barrels increased following unilateral trimming of vibrissae, which was associated with a decreased CO reactivity in the same barrels. As with the olfactory system, our present findings again revealed an inverse relationship between BACE1 expression and endogenous neuronal activity. Importantly, deprivation-induced BACE1 upregulation can occur trans-synaptically in the cerebral neocortex. Our results emphasize a biological role of BACE1 in neuronal and synaptic plasticity, but also implicate a potential mechanism whereby neuronal hypoactivity may lead to Ab overproduction and accumulation in the neocortex.
OVEREXPRESSION OF DIVALENT METAL TRANSPORTER 1 ENHANCED IRON INDUCED CELL DAMAGE Hua Min Xu, Hong Jiang, Jun Wang, Jun Xia Xie Department of Physiology, Medical College of Qingdao University, Qingdao, China Elevated iron accumulation has been reported in brain regions in some neurodegenerative disorders. However, the mechanism for this is largely unknown. Divalent metal transporter 1 (DMT1) is an important divalent cation transporter. Our previous studies have demonstrated increased DMT1 expression and elevated iron levels in the SNpc of PD mouse model, indicating the important role of increased DMT1 expression in iron accumulation. In the present study, we generated the stable MES23.5 dopaminergic cell lines with overexpression of DMT1 to investigate the role of increased DMT1 expression in cellular oxidative stress and cell damage caused by iron accumulation. Results showed that the expression of DMT1 increased significantly in stable transfected cells compared to control. The upregulation of DMT1 enhanced the iron influx inducing the subsequent increase of reactive oxygen species and reduced mitochondrial membrane potential. This led to the activation of caspase3. These results suggest that increased DMT1 expression in MES23.5 cells caused the increased intracellular iron accumulation, which resulted in the increased oxidative stress leading to ultimate cell damage. This work was supported by the grants from the National Program of Basic Research sponsored by the Ministry of Science and Technology of China (2007CB516701, 2006CB500704) and the National Foundation of Natural Science of China (No. 30400139 and 30570649).
HISTAMINE ALTERATION IN h-APP TRANSGENIC MICE WITH ALZHEIMER’S DISEASE Wen Hai Yan 1,2, Guo Dong Li 1, Huan Na Li 1, Xue Fei Han 1, Yan Xu 1,2, Ying Xing 1 1 The Stem Cells Research Center, Zhengzhou University, China 2 Department of Pathophysiology, School of Basic Medicine, Zhengzhou University, China Neurotransmitter histamine (HA) has been implicated in the regulation of numerous and important activities of the central nervous system as arousal, cognition, circadial rhythms and neuroendocrine regulation. The role of histamine in central nervous system disorders is not clearly demonstrated and
S11
contradictory results have been reported. Our study is to investigate the role of histaminergic system in central nervous system by assaying the content of histamine in hippocampus in the hApp transgenic mouse model of neurodegeneration using high performance liquid chromatography (HPLC) with fluorometric detection. Simultaneously hippocampus tissues were taken for dehydration and embedding, congo red staining and immunohistochemical staining. Our experimental data indicated the participation of histamine in AD progress. The contents of histamine in hippocampus in 3 and 6 months old App (+) mice were 12.28 1.36 and 20.65 3.45 (mg/g wet tissue weight) respectively, while in 3 and 6 months old App (-) mice HA were 9.87 1.64 and 13.45 2.11 (mg/g wet tissue weight). The data showed that concentration of HA in hippocampus increased with mice growth and HA in 6 months old App (+) mice was higher than that in 6 months old App (-) mice. Immunohistochemistry revealed plaques in hippocampus mice and Congo red staining showed amyloid deposition in intercellular space in 6 months old App (+). Our work indicates that histamine levels increase as AD progresses.
PROTECTIVE EFFECT OF HYDROGEN SULFIDE ON MPP+ INDUCED DAMAGE IN PC12 CELLS Wei Lan Yin, Xiao Qing Tang, Jian Qin He Department of Physiology, Medical School, University of South China, Hengyang, Hunan, China Hydrogen sulfide (H2S) is the third gaseous mediator apart from nitric oxide (NO) and carbon monoxide (CO). Eto K et al. show that the level of H2S in the brains of AD patients is severely decreased. However, it remains incompletely defined whether the low level hydrogen sulfide is responsible for the oxidative stress-induced neurodegeneration in Parkinons disease. To investigate the protective effect of hydrogen sulfide against MPP+ damage in PC12 cells and explore the involved underlying molecular mechanism, we used MPP+ induced PC12 cells damage as the model of Parkinons disease and pretreated with NaHS (used as H2S donor) to explore the potential protective effect. The cell shape and nuclear morphology were observed by nuclear staining with hoechst33258; the proliferation of PC12 cells was observed by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. The apoptosis of PC12 cells was detected by flow cytometry (FCM) with propidium iodide (PI) stain. The mitochondrial membrane potential (DJm) and the level of reactive oxygen species (ROS) in PC12 cells were analyzed by rhodamine123 and dihydrohodamine123 stain FCM respectively. RT-PCR and western blot were used to detect the level of Bax mRNA and protein expression of Bcl-2 and Caspase3 in the PC12 cells respectively. We found that H2S decreased the inhibition ratio, the apoptosis, and the ROS accumulation, increased the loss MMP, down-regulated Bcl-2, up-regulated Bax and Caspase-3 induced by MPP+ in PC12 cells. The results explained that H2S has neuroprotective effect against MPP+-induced damage in PC12 cells, the mechanism of which might be related to attenuate the MPP+-induced intracellular ROS generation, preserve DJm, prevent the MPP+-induced down-regulation of Bcl-2 and up-regulation of Bax and Caspase-3.
PERIPHERAL ZINC (ZN2+) INDUCED DOPAMINERGIC NEURONS APOPTOSIS IN THE NIGROSTRIATAL SYSTEM OF RATS Wen Ran Yu, Hong Jiang, Jun Wang, Jun Xia Xie Department of Physiology, Medical College of Qingdao University, Qingdao, China Clinical studies have demonstrated an excess of zinc in the substantia nigra (SN) of Parkinsonian patients, suggesting the involvement of zinc in Parkinson’s disease (PD). To demonstrate the relationship between peripheral zinc overload and dopaminergic neuron loss in rat SN and to investigate the possible mechanism, in the present study we used Inductively Coupled Plasma (ICP-2) detector, fast cyclic voltammetry, tyrosine hydroxylase (TH) immunohistochemistry, Nissl staining and high-performance liquid chromatographyelectrochemical detection to study the degeneration of dopaminergic neurons and increased zinc content in the SN of rats. Our study showed that peripheral zinc overload increased the zinc content and induced damage of dopaminergic neurons in the SN. We also observed that lipid peroxidation elevated and SOD activity decreased in the midbrain of rats. The results of Western blots showed
Reduced brain or neuronal activity and metabolism may play an important role in Alzheimer’s disease (AD) etiology, as suggested by epidemiological and imaging studies in humans. Stimulatory experimental paradigms, e.g., environmental enrichment, voluntary exercise and learning, reduce the levels and accumulation of amyloid peptides (Ab) in the cerebral cortex of transgenic mouse models of AD. Neuronal hypoactivity in the rat olfactory bulb, induced by naris-occlusion, elevates protein levels and activity of b-secretase-1 (BACE1), a prerequisite for Ab genesis. We determined BACE1 expression relative to endogenous neuronal activity, measured by cytochrome c oxidase (CO) reactivity, in the adult rhesus monkey (Macaca mulatta) striate cortex (V1) and guinea pig barrel cortex (SI) following whisker trimming. BACE1 expression in V1 occurred mainly in the neuropil over layer II-IV, appearing as alternating patches of high and low immunoreactivities. The periodic patches of BACE-1 immunoreactivity correlated spatially with CO blob and inter-blob areas, but the labeling intensities of the two markers were complementary to each other within a given area. In SI, BACE-1 expression in the barrels increased following unilateral trimming of vibrissae, which was associated with a decreased CO reactivity in the same barrels. As with the olfactory system, our present findings again revealed an inverse relationship between BACE1 expression and endogenous neuronal activity. Importantly, deprivation-induced BACE1 upregulation can occur trans-synaptically in the cerebral neocortex. Our results emphasize a biological role of BACE1 in neuronal and synaptic plasticity, but also implicate a potential mechanism whereby neuronal hypoactivity may lead to Ab overproduction and accumulation in the neocortex.
OVEREXPRESSION OF DIVALENT METAL TRANSPORTER 1 ENHANCED IRON INDUCED CELL DAMAGE Hua Min Xu, Hong Jiang, Jun Wang, Jun Xia Xie Department of Physiology, Medical College of Qingdao University, Qingdao, China Elevated iron accumulation has been reported in brain regions in some neurodegenerative disorders. However, the mechanism for this is largely unknown. Divalent metal transporter 1 (DMT1) is an important divalent cation transporter. Our previous studies have demonstrated increased DMT1 expression and elevated iron levels in the SNpc of PD mouse model, indicating the important role of increased DMT1 expression in iron accumulation. In the present study, we generated the stable MES23.5 dopaminergic cell lines with overexpression of DMT1 to investigate the role of increased DMT1 expression in cellular oxidative stress and cell damage caused by iron accumulation. Results showed that the expression of DMT1 increased significantly in stable transfected cells compared to control. The upregulation of DMT1 enhanced the iron influx inducing the subsequent increase of reactive oxygen species and reduced mitochondrial membrane potential. This led to the activation of caspase3. These results suggest that increased DMT1 expression in MES23.5 cells caused the increased intracellular iron accumulation, which resulted in the increased oxidative stress leading to ultimate cell damage. This work was supported by the grants from the National Program of Basic Research sponsored by the Ministry of Science and Technology of China (2007CB516701, 2006CB500704) and the National Foundation of Natural Science of China (No. 30400139 and 30570649).
HISTAMINE ALTERATION IN h-APP TRANSGENIC MICE WITH ALZHEIMER’S DISEASE Wen Hai Yan 1,2, Guo Dong Li 1, Huan Na Li 1, Xue Fei Han 1, Yan Xu 1,2, Ying Xing 1 1 The Stem Cells Research Center, Zhengzhou University, China 2 Department of Pathophysiology, School of Basic Medicine, Zhengzhou University, China Neurotransmitter histamine (HA) has been implicated in the regulation of numerous and important activities of the central nervous system as arousal, cognition, circadial rhythms and neuroendocrine regulation. The role of histamine in central nervous system disorders is not clearly demonstrated and
S11
contradictory results have been reported. Our study is to investigate the role of histaminergic system in central nervous system by assaying the content of histamine in hippocampus in the hApp transgenic mouse model of neurodegeneration using high performance liquid chromatography (HPLC) with fluorometric detection. Simultaneously hippocampus tissues were taken for dehydration and embedding, congo red staining and immunohistochemical staining. Our experimental data indicated the participation of histamine in AD progress. The contents of histamine in hippocampus in 3 and 6 months old App (+) mice were 12.28 1.36 and 20.65 3.45 (mg/g wet tissue weight) respectively, while in 3 and 6 months old App (-) mice HA were 9.87 1.64 and 13.45 2.11 (mg/g wet tissue weight). The data showed that concentration of HA in hippocampus increased with mice growth and HA in 6 months old App (+) mice was higher than that in 6 months old App (-) mice. Immunohistochemistry revealed plaques in hippocampus mice and Congo red staining showed amyloid deposition in intercellular space in 6 months old App (+). Our work indicates that histamine levels increase as AD progresses.
PROTECTIVE EFFECT OF HYDROGEN SULFIDE ON MPP+ INDUCED DAMAGE IN PC12 CELLS Wei Lan Yin, Xiao Qing Tang, Jian Qin He Department of Physiology, Medical School, University of South China, Hengyang, Hunan, China Hydrogen sulfide (H2S) is the third gaseous mediator apart from nitric oxide (NO) and carbon monoxide (CO). Eto K et al. show that the level of H2S in the brains of AD patients is severely decreased. However, it remains incompletely defined whether the low level hydrogen sulfide is responsible for the oxidative stress-induced neurodegeneration in Parkinons disease. To investigate the protective effect of hydrogen sulfide against MPP+ damage in PC12 cells and explore the involved underlying molecular mechanism, we used MPP+ induced PC12 cells damage as the model of Parkinons disease and pretreated with NaHS (used as H2S donor) to explore the potential protective effect. The cell shape and nuclear morphology were observed by nuclear staining with hoechst33258; the proliferation of PC12 cells was observed by 3-[4,5-dimethylthiazol-2-yl]-2, 5-diphenyltetrazolium bromide (MTT) assay. The apoptosis of PC12 cells was detected by flow cytometry (FCM) with propidium iodide (PI) stain. The mitochondrial membrane potential (DJm) and the level of reactive oxygen species (ROS) in PC12 cells were analyzed by rhodamine123 and dihydrohodamine123 stain FCM respectively. RT-PCR and western blot were used to detect the level of Bax mRNA and protein expression of Bcl-2 and Caspase3 in the PC12 cells respectively. We found that H2S decreased the inhibition ratio, the apoptosis, and the ROS accumulation, increased the loss MMP, down-regulated Bcl-2, up-regulated Bax and Caspase-3 induced by MPP+ in PC12 cells. The results explained that H2S has neuroprotective effect against MPP+-induced damage in PC12 cells, the mechanism of which might be related to attenuate the MPP+-induced intracellular ROS generation, preserve DJm, prevent the MPP+-induced down-regulation of Bcl-2 and up-regulation of Bax and Caspase-3.
PERIPHERAL ZINC (ZN2+) INDUCED DOPAMINERGIC NEURONS APOPTOSIS IN THE NIGROSTRIATAL SYSTEM OF RATS Wen Ran Yu, Hong Jiang, Jun Wang, Jun Xia Xie Department of Physiology, Medical College of Qingdao University, Qingdao, China Clinical studies have demonstrated an excess of zinc in the substantia nigra (SN) of Parkinsonian patients, suggesting the involvement of zinc in Parkinson’s disease (PD). To demonstrate the relationship between peripheral zinc overload and dopaminergic neuron loss in rat SN and to investigate the possible mechanism, in the present study we used Inductively Coupled Plasma (ICP-2) detector, fast cyclic voltammetry, tyrosine hydroxylase (TH) immunohistochemistry, Nissl staining and high-performance liquid chromatographyelectrochemical detection to study the degeneration of dopaminergic neurons and increased zinc content in the SN of rats. Our study showed that peripheral zinc overload increased the zinc content and induced damage of dopaminergic neurons in the SN. We also observed that lipid peroxidation elevated and SOD activity decreased in the midbrain of rats. The results of Western blots showed