1
|
Xia L, Wang Z, Zhang Y, Yang X, Zhan Y, Cheng R, Wang S, Zhang J. Reciprocal regulation of insulin and plasma 5'-AMP in glucose homeostasis in mice. J Endocrinol 2015; 224:225-34. [PMID: 25512345 DOI: 10.1530/joe-14-0501] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.6] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Journal Information] [Submit a Manuscript] [Subscribe] [Scholar Register] [Indexed: 12/31/2022]
Abstract
A previous investigation has demonstrated that plasma 5'-AMP (pAMP) exacerbates and causes hyperglycemia in diabetic mice. However, the crosstalk between pAMP and insulin signaling to regulate glucose homeostasis has not been investigated in depth. In this study, we showed that the blood glucose level was more dependent on the ratio of insulin to pAMP than on the absolute level of these two factors. Administration of 5'-AMP significantly attenuated the insulin-stimulated insulin receptor (IR) autophosphorylation in the liver and muscle tissues, resulting in the inhibition of downstream AKT phosphorylation. A docking analysis indicated that adenosine was a potential inhibitor of IR tyrosine kinase. Moreover, the 5'-AMP treatment elevated the ATP level in the pancreas and in the isolated islets, stimulating insulin secretion and increasing the plasma level of insulin. The insulin administration decreased the 5'-AMP-induced hyper-adenosine level by the up-regulation of adenosine kinase activities. Our results indicate that blood glucose homeostasis is reciprocally regulated by pAMP and insulin.
Collapse
Affiliation(s)
- Lin Xia
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Zhongqiu Wang
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Ying Zhang
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Xiao Yang
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Yibei Zhan
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Rui Cheng
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Shiming Wang
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| | - Jianfa Zhang
- Center for Molecular MetabolismNanjing University of Science and Technology, B508, #364, 200 Xiaolingwei Street, Nanjing 210094, ChinaDepartment of RadiologyNanjing University of Chinese Medicine, Nanjing 210000, ChinaDepartment of Biochemistry and Molecular BiologyJiangsu University School of Medicine, Zhenjiang 212013, China
| |
Collapse
|
2
|
Chronic morphine treatment impaired hippocampal long-term potentiation and spatial memory via accumulation of extracellular adenosine acting on adenosine A1 receptors. J Neurosci 2010; 30:5058-70. [PMID: 20371826 DOI: 10.1523/jneurosci.0148-10.2010] [Citation(s) in RCA: 75] [Impact Index Per Article: 5.4] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/21/2022] Open
Abstract
Chronic exposure to opiates impairs hippocampal long-term potentiation (LTP) and spatial memory, but the underlying mechanisms remain to be elucidated. Given the well known effects of adenosine, an important neuromodulator, on hippocampal neuronal excitability and synaptic plasticity, we investigated the potential effect of changes in adenosine concentrations on chronic morphine treatment-induced impairment of hippocampal CA1 LTP and spatial memory. We found that chronic treatment in mice with either increasing doses (20-100 mg/kg) of morphine for 7 d or equal daily dose (20 mg/kg) of morphine for 12 d led to a significant increase of hippocampal extracellular adenosine concentrations. Importantly, we found that accumulated adenosine contributed to the inhibition of the hippocampal CA1 LTP and impairment of spatial memory retrieval measured in the Morris water maze. Adenosine A(1) receptor antagonist 8-cyclopentyl-1,3-dipropylxanthine significantly reversed chronic morphine-induced impairment of hippocampal CA1 LTP and spatial memory. Likewise, adenosine deaminase, which converts adenosine into the inactive metabolite inosine, restored impaired hippocampal CA1 LTP. We further found that adenosine accumulation was attributable to the alteration of adenosine uptake but not adenosine metabolisms. Bidirectional nucleoside transporters (ENT2) appeared to play a key role in the reduction of adenosine uptake. Changes in PKC-alpha/beta activity were correlated with the attenuation of the ENT2 function in the short-term (2 h) but not in the long-term (7 d) period after the termination of morphine treatment. This study reveals a potential mechanism by which chronic exposure to morphine leads to impairment of both hippocampal LTP and spatial memory.
Collapse
|
3
|
Alanko L, Heiskanen S, Stenberg D, Porkka-Heiskanen T. Adenosine kinase and 5'-nucleotidase activity after prolonged wakefulness in the cortex and the basal forebrain of rat. Neurochem Int 2003; 42:449-54. [PMID: 12547643 DOI: 10.1016/s0197-0186(02)00155-9] [Citation(s) in RCA: 22] [Impact Index Per Article: 1.0] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/27/2022]
Abstract
The effect of prolonged wakefulness on adenosine kinase (AK), ecto-5'-nucleotidase and endo-5'-nucleotidase activity was assessed in the present study. Rats were sleep deprived for 3 or 6h, and one group was allowed to sleep 2h of recovery sleep after the 6h deprivation. The cortex and the basal forebrain were dissected, and frozen rapidly on dry ice. The enzyme activity of adenosine kinase was measured by monitoring the conversion of [2-3H]-adenosine into [3H]-adenosine monophosphate (AMP) and the ecto-5'-nucleotidase and endo-5'-nucleotidase activities by monitoring the conversion of [2-3H]-AMP into [3H]-adenosine. The enzyme activities did not change during deprivation or recovery sleep in either cortex or basal forebrain when compared to unhandled controls. Significant diurnal variation in enzyme activities was noted in both brain areas. In the basal forebrain adenosine kinase and both nucleotidases showed their lowest activity in the middle of the rest phase, 6h after lights on, suggesting a low level of adenosine metabolism, both production and degradation at this time point. In the cortex adenosine kinase had a diurnal activity pattern similar to the basal forebrain and the ecto-5'-nucleotidase activity was low already early in the rest phase, 3h after lights on, and remained low until the end part of the rest phase, 8h after lights on. Endo-5'-nucleotidase lacked diurnal variation. These activity patterns may be associated with the lower level of energy metabolism during sleep compared to wakefulness.
Collapse
Affiliation(s)
- Lauri Alanko
- Institute of Biomedicine/Physiology, University of Helsinki, P.O. Box 63, FIN-00014 Helsinki, Finland.
| | | | | | | |
Collapse
|
4
|
Mackiewicz M, Geiger JD, Pack AI. Simultaneous assessment of ecto- and cytosolic-5'-nucleotidase activities in brain micropunches. J Neurosci Methods 2000; 104:9-18. [PMID: 11163406 DOI: 10.1016/s0165-0270(00)00314-9] [Citation(s) in RCA: 8] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [MESH Headings] [Grants] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/19/2022]
Abstract
We propose a new methodology for simultaneous assessment of ecto- and cytosolic-5'-nucleotidase that can be utilized in brain to measure the activity of these enzymes in micropunches of tissues. It is based on the differential sensitivity of both enzymes to alpha,beta-methyleneadenosine 5'-diphosphate (AMP-CP) and the requirements for magnesium as a co-factor. The design of assay protocol contains an internal validation by allowing comparisons between total level of 5'-nucleotidase activity with that calculated from the sum of individual activities of the ecto- and cytosolic-5'-nucleotidases. We have applied this new approach to assess the activity of ecto- and cytosolic-5'-nucleotidase in the brain regions relevant to sleep regulation. The level of both enzymes was significantly lower in the cerebral cortex than other brain regions tested.
Collapse
Affiliation(s)
- M Mackiewicz
- Center for Sleep and Respiratory Neurobiology, University of Pennsylvania School of Medicine, 3600 Spruce Street, 991 Maloney Building, Philadelphia, PA 19104-4283, USA.
| | | | | |
Collapse
|