Objective： To investigated whether epigenetic mechanisms contribute to the variable expression of variable protease nexin1（PN-1） encoded by the SERPINE2 gene in different cell types. Methods： Working with 5 human ...Objective： To investigated whether epigenetic mechanisms contribute to the variable expression of variable protease nexin1（PN-1） encoded by the SERPINE2 gene in different cell types. Methods： Working with 5 human cell lines, we determined the CpG methylation status within two CpG islands in the SERPINE2 gene by bisulphate sequencing and the PN-1 mRNA level by Q-RT PCR. Results： A CpG island spanning the transcription initiation site showed little methylation in 3 of the cell lines and substantial methylation in 2 of the cell lines. A CpG island covering the translation starting site showed full methylation in all investigated cell lines. Methylation within the CpG island was not randomly distributed, but showed accumulation at specific sites. However, we were not able to distinguish any patterns which related the methylation frequency to the gene expression level. Inhibition of CpG methylation with 5-aza-2’-deoxycytidine led to a several fold increase in PN-1 mRNA levels, but based on the results on CpG methylation in the CpG island spanning the transcript, the effect is most likely indirect. Conclusion： We have carefully mapped the CpG methylation pattern in two CpG islands in the 5’ part of the SERPINE2 gene without finding any obvious inverse correlation between methylation frequency and expression level.展开更多
The neuro-glial interface extends far beyond mechanical support alone and includes interactions through coagulation cascade proteins. Here, we systematically review the evidence indicating that synaptic and node of Ra...The neuro-glial interface extends far beyond mechanical support alone and includes interactions through coagulation cascade proteins. Here, we systematically review the evidence indicating that synaptic and node of Ranvier glia cell components modulate synaptic transmission and axonal conduction by a coagulation cascade protein system, leading us to propose the concept of the neuro-glial coagulonome. In the peripheral nervous system, the main thrombin receptor protease activated receptor 1 (PAR1) is located on the Schwann microvilli at the node of Ranvier and at the neuromuscular junction. PAR1 activation effects can be both neuroprotective or harmful, depending on thrombin activity levels. Low physiological levels of thrombin induce neuroprotective effects in the Schwann cells which are mediated by the endothelial protein C receptor. High levels of thrombin induce conduction deficits, as found in experimental autoimmune neuritis, the animal model for Guillaine-Barre syndrome. In the central nervous system, PAR1 is located on the peri-synaptic astrocyte end-feet. Its activation by high thrombin levels is involved in the pathology of primary inflammatory brain diseases such as multiple sclerosis, as well as in other central nervous system insults, including trauma, neoplasms, epilepsy and vascular injury. Following activation of PAR1 by high thrombin levels the seizure threshold is lowered. On the other hand, PAR1 activation by lower levels of thrombin in the central nervous system protects against a future ischemic insult. This review presents the known structure and function of the neuro-glial coagulonome, focusing on coagulation, thrombin and PAR1 in a pathway which may be either physiological (neuroprotective) or detrimental in peripheral nervous system and central nervous system diseases. Understanding the neuro-glial coagulonome may open opportunities for novel pharmacological interventions in neurological diseases.展开更多
Background Intracerebral hemorrhage （ICH） can cause brain damage through a number of pathways.The purpose of the study was to explore the effect of thrombin, protease nexin-1 （PN-1） and protease activated receptor...Background Intracerebral hemorrhage （ICH） can cause brain damage through a number of pathways.The purpose of the study was to explore the effect of thrombin, protease nexin-1 （PN-1） and protease activated receptor-1 （PAR-1） in rat and human cerebellum after ICH.Methods A model of ICH was produced in adult Sprague-Dawley rats by direct injection of autologous blood （50 μl） into caudate nucleus.Patients with injured hemorrhage were also enrolled in this study.Different expressions of thrombin,PAR-1, PN-1 were detected in rat and human cerebellum by immunohistochemistry and in situ hybridization.Results In rat cerebellum, thrombin protein significantly increased at 6 hours and reached the maximum 2 days afterICH.The expression of PAR-1 protein reached the maximum at 24-48 hours, and then began to decrease.The expression of PN-1 protein reached the maximum at 3 hours, decreased somewhat after that and increased a little at 5days after ICH.While in human cerebellum, the changing tendency of thrombin, PAR-1 and PN-1 was almost conform to the rat.Conclusion In cerebellum, thrombin can activate PAR-1 expression after ICH, and PN-1 appears quickly after ICH in order to control the deleterious effect of thrombin.展开更多
基金supported by the Danish National Research Foundation (26-331-6)the Danish Cancer Society (DP 07043, DP 08001)Grosserer Alfred Nielsen and Hustrus Fond
文摘Objective： To investigated whether epigenetic mechanisms contribute to the variable expression of variable protease nexin1（PN-1） encoded by the SERPINE2 gene in different cell types. Methods： Working with 5 human cell lines, we determined the CpG methylation status within two CpG islands in the SERPINE2 gene by bisulphate sequencing and the PN-1 mRNA level by Q-RT PCR. Results： A CpG island spanning the transcription initiation site showed little methylation in 3 of the cell lines and substantial methylation in 2 of the cell lines. A CpG island covering the translation starting site showed full methylation in all investigated cell lines. Methylation within the CpG island was not randomly distributed, but showed accumulation at specific sites. However, we were not able to distinguish any patterns which related the methylation frequency to the gene expression level. Inhibition of CpG methylation with 5-aza-2’-deoxycytidine led to a several fold increase in PN-1 mRNA levels, but based on the results on CpG methylation in the CpG island spanning the transcript, the effect is most likely indirect. Conclusion： We have carefully mapped the CpG methylation pattern in two CpG islands in the 5’ part of the SERPINE2 gene without finding any obvious inverse correlation between methylation frequency and expression level.
文摘The neuro-glial interface extends far beyond mechanical support alone and includes interactions through coagulation cascade proteins. Here, we systematically review the evidence indicating that synaptic and node of Ranvier glia cell components modulate synaptic transmission and axonal conduction by a coagulation cascade protein system, leading us to propose the concept of the neuro-glial coagulonome. In the peripheral nervous system, the main thrombin receptor protease activated receptor 1 (PAR1) is located on the Schwann microvilli at the node of Ranvier and at the neuromuscular junction. PAR1 activation effects can be both neuroprotective or harmful, depending on thrombin activity levels. Low physiological levels of thrombin induce neuroprotective effects in the Schwann cells which are mediated by the endothelial protein C receptor. High levels of thrombin induce conduction deficits, as found in experimental autoimmune neuritis, the animal model for Guillaine-Barre syndrome. In the central nervous system, PAR1 is located on the peri-synaptic astrocyte end-feet. Its activation by high thrombin levels is involved in the pathology of primary inflammatory brain diseases such as multiple sclerosis, as well as in other central nervous system insults, including trauma, neoplasms, epilepsy and vascular injury. Following activation of PAR1 by high thrombin levels the seizure threshold is lowered. On the other hand, PAR1 activation by lower levels of thrombin in the central nervous system protects against a future ischemic insult. This review presents the known structure and function of the neuro-glial coagulonome, focusing on coagulation, thrombin and PAR1 in a pathway which may be either physiological (neuroprotective) or detrimental in peripheral nervous system and central nervous system diseases. Understanding the neuro-glial coagulonome may open opportunities for novel pharmacological interventions in neurological diseases.
基金This study was supported by grants of the National Natural Science Foundation of Heilongjiang Province, China （No. ZJY0705）, and the Foundation of the First Clinical Hospital of Harbin Medical University, China （No. Y08-009）.
文摘Background Intracerebral hemorrhage （ICH） can cause brain damage through a number of pathways.The purpose of the study was to explore the effect of thrombin, protease nexin-1 （PN-1） and protease activated receptor-1 （PAR-1） in rat and human cerebellum after ICH.Methods A model of ICH was produced in adult Sprague-Dawley rats by direct injection of autologous blood （50 μl） into caudate nucleus.Patients with injured hemorrhage were also enrolled in this study.Different expressions of thrombin,PAR-1, PN-1 were detected in rat and human cerebellum by immunohistochemistry and in situ hybridization.Results In rat cerebellum, thrombin protein significantly increased at 6 hours and reached the maximum 2 days afterICH.The expression of PAR-1 protein reached the maximum at 24-48 hours, and then began to decrease.The expression of PN-1 protein reached the maximum at 3 hours, decreased somewhat after that and increased a little at 5days after ICH.While in human cerebellum, the changing tendency of thrombin, PAR-1 and PN-1 was almost conform to the rat.Conclusion In cerebellum, thrombin can activate PAR-1 expression after ICH, and PN-1 appears quickly after ICH in order to control the deleterious effect of thrombin.
